The present invention relates generally to a paint spray booth for spray painting articles and in particular to a fluid wash scrubber for capture of overspray paint particles in a paint spray booth.
Paint spray booths, particularly for use in production of larger articles such as automobile bodies, comprise a housing through which the article to be painted is moved longitudinally on a conveyor. The paint can be applied automatically by robots or the paint can be applied manually. With either method of application, there is a certain amount of paint which does not contact the target object and forms airborne overspray within the spray booth atmosphere. It is necessary to provide ventilation to remove the overspray from the paint booth to maintain the booth in proper condition and to provide a clean atmosphere for workers in the booth.
Air is typically blown through the spray booth in one direction to remove the overspray from the spray booth atmosphere. After the overspray has been removed from the spray booth, it is necessary to remove the overspray paint particles from the ventilation air before either recirculating the air or exhausting the air to the environment. One way to remove the overspray paint particles from the air is with a liquid wash scrubber which entraps the paint particles within a liquid, typically water, after which the paint is separated from the liquid for proper disposal.
In many prior art spray booths of the so called downdraft type the paint laden air and water flow downwardly through a grid on the floor of the booth into a scrubber in which the water and paint laden air are thoroughly intermixed and agitated to enable the paint particles to be entrapped in the water. Although prior art scrubbers for downdraft paint booths operate generally satisfactorily, there is a continuing need to enhance their performance in removing airborne paint and further to reduce their vertical height which affects the overall height of the spray booth.
It is an object of the present invention therefore, to provide a fluid wash scrubber for a paint booth in which the vertical height of the scrubber is minimized to reduce the overall height of the booth. It is a feature of the present invention to provide a liquid wash scrubber in which the air and liquid intermix in a substantially horizontal flow direction to reduce the scrubber height. It is a further object of this invention to reduce overspray paint emissions from the spray booth.
The paint spray booth of the present invention comprises a housing having a base and an intermediate horizontal floor spaced above the base dividing the housing into an upper chamber and a lower chamber. Objects to the painted are conveyed longitudinally through the upper chamber in a conventional manner. The horizontal intermediate floor is a grated floor which allows ventilation air to flow through the floor. The spray booth of the present invention includes downdraft ventilation in which air is blown into the spray booth from the ceiling of the booth and directed downward.
The downwardly flowing air removes overspray paint particles from the upper chamber and carries these particles through the grated floor to the lower chamber which contains the liquid wash scrubber. In the scrubber, the air is mixed with liquid, typically water, which entraps the paint overspray particles to remove the paint particles from the air to purify the air. The scrubber provides a flow path for the air and water in which the mixture flows downwardly, then laterally through an orifice, and then upwardly over a baffle. The flow path through the scrubber creates turbulence in the water to ensure complete mixing of the water and air in the scrubber. The lower chamber includes an air exhaust vent along one lateral side of the scrubber which is positioned in the side of the lower chamber opposite the direction of the water flow path through the scrubber. This results in the air in the scrubber being drawn through the water to further ensure complete removal of paint from the water. By providing a substantially horizontal flow path for the water and air through the scrubber, the overall height of the scrubber and the lower chamber can be reduced to enable a reduction in the overall height of the spray booth.
Further objects, features and advantages of the invention will become apparent from a consideration of the following description and the appended claims when taken in connection with the accompanying drawings.